Update Footer link href (#2950)

Author: vladdenisov

src/components/LayoutFooter/Footer.js

@@ -122,7 +122,7 @@ const Footer = ({layoutHasSidebar = false}: {layoutHasSidebar: boolean}) => (
             },
           }}>
           <a
-            href="https://code.facebook.com/projects/"
+            href="https://opensource.facebook.com/projects/"
             target="_blank"
             rel="noopener">
             <img